DESCRIPTION (provided by investigator): The American Thoracic Society (ATS) and the Infectious Diseases Society of America (IDSA) have periodically published guidelines on the diagnosis and management of pneumonia. In 2005, the ATS/IDSA published guidelines which define a new subset of pneumonia entitled Health Care Associated Pneumonia (HCAP). HCAP pertains to patients that have frequently interacted with the Health Care system prior to pneumonia, which is thought to increase risk for infections caused by multiple drug-resistant (MDR) bacteria. The guidelines recommend aggressive diagnosis and antibiotic treatment regimens for HCAP. Research specific to HCAP is limited and the guideline recommendations have been questioned. Proposal Aims include: 1) to compare clinical outcome of patients with HCAP that receive standard community acquired pneumonia (CAP) therapy to those that receive alternative therapy such as guideline similar therapy (GTS)]; 2) identify risk factors for MDR bacteria including Methicillin-Resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, compared to non-MDR bacteria and develop models that accurately identify patients infected with MDR. This will be a multi- center retrospective cohort study of Veterans Affairs Medical Center inpatients with HCAP. Propensity score matching will be used to adjust for potential confounding and selection bias associated with non-random treatment allocation. Generalized estimating equations will be used to characterize associations between 30-day survival and treatments: standard CAP; anti-MRSA and anti-Pseudomonas or GST, anti-MRSA, anti-Pseudomonas, or other therapies. In Aim 2 MDR status will be determined for all subjects. Logistic regression will be used to develop descriptive models of MDR risk based on non-HCAP specific risk criteria reported in the guidelines as well as HCAP specific data from the cohort. The process will be repeated for specific MDR pathogens: MRSA and Pseudomonas aeruginosa. The best model of MDR status will be refitted with MRSA and Pseudomonas aeruginosa data and compared to pathogen- specific derived models. The proposed study will determine whether adherence to HCAP guideline recommended treatments improve survival. Further developing specific prediction rules for MDR pathogens will refine future empirical HCAP antibiotic selection. Finally, determining which patients may benefit most from empirical MDR directed antibiotic therapy may help to limit antibiotic resistance. R&R: Other Project Materials 7. PUBLIC HEALTH RELEVANCE Patients with exposure to the Health Care system resources are at increased risk for infections caused by antibiotic resistant bacteria. The purpose of this study is to determine how frequently antibiotic resistant bacteria cause Health Care Associated pneumonia, what type of Health Care exposures are related to developing a pneumonia due to resistant bacteria, and what antibiotic treatment combinations work the best for Health Care Associated pneumonia. This study will improve public health by helping health care providers choose the right antibiotics when treating Health Care Associated pneumonia and not using more antibiotics than necessary. [unreadable] [unreadable] [unreadable] [unreadable] [unreadable]